Francisco do Amaral (r) says he is only standing to give the voters a choice

The former guerrilla leader was accompanied by his opponent Francisco Xavier do Amaral when he cast his ballot at a polling station in the capital, Dili, to applause from onlookers.

Reflecting the good nature of the campaign, the two men embraced before voting one after the other in the poll which is East Timor's last step to independence after centuries of foreign domination - first by Portugal and, since 1975, by Indonesia.

Mr Gusmao, 55, is virtually assured of victory, with Mr Amaral saying he is standing merely to give the 430,000 registered voters a choice.

People appreciate the chance to vote after centuries of colonisation

Voting started slowly on Sunday morning (2200 GMT on Saturday), but picked up significantly as people went to polling stations after attending church to celebrate Mass.

Polling stations were due to close at 1600 (0700 GMT) on Sunday, but electoral officials said voters already in the queue were still casting their ballots after this time.

Counting is due to begin on Monday and results are expected later in the week.

The BBC's Richard Galpin in Dili says the election seems to have gone ahead very smoothly, with no reports of any serious trouble.

Determined

Mr Valenzuela said earlier that all 933 polling stations across East Timor were operating smoothly.

He admitted that he had been surprised by the early absence of voters in Dili which contrasted with the long lines outside regional booths.